SCSInet
- Thread starter scubanoah
- Start date
scsinet
Active Member
Golly... as flattered as I am when someone puts a question to me directly, I have to admit that I'm not the best at nitty gritty comparisons between lamps. I've heard that XM, Ushio, and Radium all offer very good performance, but having not seen these lamps side by side and lacking a photometer, I certainly can't say with any authority.
IMO though there is not a terribly great difference in PAR from manufacturer to manufacturer over and above the manufacturing tolerances. In other words, one lamp from a particular brand versus another lamp of exactly the same type and brand may fluctuate in performance as much as a certain lamp from one manufacturer versus a identical rated lamp from another; the way metal halide lamps are constructed there are always variances.
So long story short, I think if you stick with those brands above, you will be okay no matter what you do.
IMO though there is not a terribly great difference in PAR from manufacturer to manufacturer over and above the manufacturing tolerances. In other words, one lamp from a particular brand versus another lamp of exactly the same type and brand may fluctuate in performance as much as a certain lamp from one manufacturer versus a identical rated lamp from another; the way metal halide lamps are constructed there are always variances.
So long story short, I think if you stick with those brands above, you will be okay no matter what you do.
scubanoah
Member
Thanks much for the input. i currently have the 15k XM bulbs but they are about due for replacement. I like the color but they dont seem to be as "bright" as some other bulbs I have used. I know you cant judge by what your eyes see. I figured you would have a photometer, cmon man quit slacking. jkjk.
reefraff
Active Member
The xm 15K lamp is pitiful as far as PAR output. It is lower than their 20K lamp. I will post a link I think is OK here but just in case I will describe what it shows. It is the output of a 175 watt Iwasaki 15000K verses a 250 watt XM 15000K. The 175 watt Iwasaki lamp has more PAR! There are 2 number in the graph. PPFD is PAR, CCT is the color. A "20000K" halide lamp has an actual color that is about 50000K. A slightly bluish 14K lamp will be around 20000K. The equipment used to test the lamps maxs out at something like 23000K so any lamp with much blue to it at all will read 0. The XM reads 0, the Iwasaki is just over 15000K which means it is a very bright lamp with a little blue in the output.
The lines on the graph represent the spectral output of the lamp. around 500nm is starting blue, 600 is starting red
The lines on the graph represent the spectral output of the lamp. around 500nm is starting blue, 600 is starting red